XP and Ant
This material is from Chapter 1, XP and Ant, from the book Extreme Programming with Ant: Building and Deploying Java Applications with JSP, EJB, XSLT, XDoclet, and JUnit (ISBN: 0-672-32562-4) written by Glenn Niemeyer and Jeremy Poteet, published by Sams Publishing.
Chapter 1: XP and Ant
What Is XP?
The XP Process
Ant and the XP Process
The Scope of This Book
Extreme Programming (XP) is a software development methodology for delivering quality software while maintaining a focus on customer satisfaction. Ant is an open-source tool from the Apache Project for creating build and deployment processes. In this book, you will learn how to implement effective XP processes by using Ant.
What Is XP?
XP development is iterative in nature, and delivers quality software through continuous automated testing and integration. XP development demands simplicity. It means refactoring code that is working to eliminate duplicate or redundant code. It is a focus on the here and now, not on what might be needed a week from now. XP emphasizes constant communication between customer and developers, as well as between developers. In fact, in XP, the customer is part of the team. XP is similar to the just-in-time inventory practices in manufacturing.
Characteristics of XP
XP maintains a focus on customer satisfaction. In XP, the customer is part of the team. That means that the customer has visibility and plays an important role in the overall plan. The customer drives the implementation and releases through writing user stories and participating in the Release Planning meetings. Because software is developed iteratively in XP, a working system is always available with some level of functionality. The customer can always view this working system and assess the state of the project or make changes in the system requirements (user stories). That also means that if the customer pulls the plug on the project, he or she will have something of value to show for the investment made to date.
XP emphasizes teamwork. Developers work in pairs on production code, and they communicate with each other. The customer, or at least a customer representative, is co-located with the development team to answer questions that naturally arise. Everyone on the development team works in different areas of the system, and everyone has ownership of the code. The XP methodology facilitates teamwork and requires trust among the team members.
Using XP adds agility to a project. Because of XP's emphasis on simplicity, quality, and testing, an XP project can more easily adapt to unforeseen circumstances than other heavier-weight methodologies can. In fact, XP expects the unexpected. That's why there is the emphasis on delivering functionality as it's needed, and testing and integrating continuously. Developers are always implementing user stories and delivering functionality as it's needed.
In XP, integration problems are caught early. This is because XP is iterative. Builds, unit testing, integration, and acceptance testing are done continuously. You don't have to go through months of coding followed by a death-march type of integration cycle. Integration is easier because it's happening all of the time. If someone starts to diverge on a meaningless tangent in code development (which is unlikely with pair-programming, and the emphasis on implementing stories), the miscue is caught early, before it has a major impact on schedule.
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